Mozlog currently has two implementations. The top level package is based on the logging module and is
deprecated. The newer structured logging implementation lives in mozlog.structured. This patch swaps the
two, so the top level mozlog module contains the recommended implementation, while mozlog.unstructured
contains the old one.
This extends the upstream update script with steps for pushing
local changes to upstream. The general approach is to look for all
commits to the tests directory since the last sync, rewrite those
so they apply to upstream at the last sync point, then rebase onto
the sync commit, before creating and merging a PR for each in turn.
